Magnet levitation has many possible applications. U.S. Pat. No. 5,099,216, “Magnetically Levitated Apparatus,” to Pelrine, discusses magnetically levitated robotic manipulators. The manipulators have attached magnetically active components, such as permanent magnets, upon which magnetic forces are imposed by fields generated by electromagnets. The discussion also addresses stability and damping of the motion of the robotic manipulators, where the manipulators can move with six degrees of freedom.
U.S. Pat. No. 5,396,136, “Magnetic Field Levitation,” to Pelrine, discusses the use of a magnetic member having an array of magnets and a diamagnetic or other material having magnetic permeability of less than one. The diamagnetic material acts as a base defining an area over which the magnetic member can levitate and be moved by external magnetic forces. In some embodiments, the diamagnetic material does not fully levitate the magnetic member but provides lift forces that reduce the effective load of the magnetic member on a moving surface.
These approaches generally rely upon an array of electromagnets to provide the magnetic fields to act upon the magnetic robots. The arrays of electromagnets determine the regions upon which the robots can be controlled by the fields generated by the electromagnets. While these arrays provide reasonably precise control of the robots, they still require electromagnets to provide the external forces that act on the robots. Another approach, discussed in U.S. Pat. No. 6,858,184, “Microlaboratory Devices and Methods,” uses a substrate having within it biasing elements in conjunction with an array of drive elements above the substrate. The drive elements move the magnetic elements in the space between the drive elements and the substrate.
In a different approach, the fields to levitate the magnetic robots may originate from current passing through conductive traces layered in a circuit substrate. Such approaches are discussed in U.S. patent application Ser. Nos. 12/960,424 and 13/270,151, incorporated by reference in their entirety here. These approaches allow for greater flexibility in the structure and uses of the manipulators, as well as their movement.